Tuesday, November 10, 2015

I've previously described an "ultrasound win," where bedside US helped prevent an unneeded (and fruitless) procedural sedation. In this case, the ultrasound is used to confirm an infrequent type of dislocation.

The Case
A young muscular male had been in a car accident. Despite devastating damage to the vehicle, he only complained of left shoulder pain. An x-ray of the shoulder was obtained...

...and suggested a posterior dislocation of the shoulder. Quite unusual!

The x-ray shows at least 3 radiographic signs supporting a posterior dislocation: A rim sign (the two red lines), a light bulb sign (outlined by, well, the light bulb), and the "Mouzopoulos sign"(hightlighted by the blue "M".").

Nonetheless, some doubt remained, since posterior shoulder dislocations are infrequent, and we wanted the diagnosis to be certain before breaking out the propofol! So we did an ultrasound of the shoulder.

Ultrasound for the .. Wait, "win" is already taken?
The probe was place in transverse orientation across the posterior aspect of the left shoulder, probe marker pointing laterally, to the patient's left:

Lemme annotate that for you:

The humeral head is clearly posterior to the glenoid, conforming a posterior dislocation. Compare this with a normal left shoulder where the humeral head is well-seated in the glenoid:

Bottom line:The next time you have any concern about the shoulder, grab a quick posterior view, even if you are already getting an x-ray.

Monday, August 31, 2015

This isn't rocket science, right? If your hypoxic patient has a high BNP and a wet CXR, then you give then a diuretic, and admit them. Done, next patient!Some POCUS skeptics would argue, however, that using echo in CHF doesn't really affect diagnosis or management. Of course,
many of these same clinicians unironically carry a modern version of the sacred hollow stick around their
necks...

The Case:

An elderly male with a history of systolic & diastolic CHF is brought in by EMS. He describes an acute onset of dyspnea and wheezing 1 hour prior. Worse with lying down and exertion. Denies recent leg swelling or
weight gain, and denies fevers, chills, or sputum.
His systolic BP is > 200 mm Hg. No JVD, but prominent
wheezing diffusely.

Before the CXR, ECG, or labs can be obtained, a focused ultrasound is performed.

A flat, collapsing IVC, but…

… numerous B-lines in the bilateral anterior apices, while …

… the EF appears to be only moderately
decreased (chronic, per the last echo in the record).

So how does clinical
care change based on the ultrasound?

The patient probably doesn’t have volume overload, given the
markedly flat IVC. Indeed, he may actually be hyPOvolemic.

The dramatic “hive” of B-lines in the anterior apices, however,
suggests that he nonetheless has quite a bit of water in his lungs.*** Plenty of research has shown that
the number of B-lines is
proportional to increases in pulmonary wedge pressure, to increases in extravascular lung water, and even increases in BNP. So, despite the flat IVC, he most likely has acute decompensated heart failure, due to diastolic heart failure (Scott Weingart has referred to this as SCAPE).He isn’t volume overloaded, just volume maldistributed!

(*** Yes, a number of other etiologies can produce B-lines/acute interstitial syndrome. But:

Bilateral B-lines suggest against pneumonia;

Acute development weigh against pulmonary fibrosis or pneumonitis; and

Absence of another severe disease did not support ARDS.)

Treatment

Since the echo suggests that high systemic vascular
resistance is the problem, and not sheer volume overload, he is given 3 nitroglycerin
tabs under the tongue (yes, 3 tabs at
once).

His wheezing stops almost instantly, like someone had flicked a
switch. The pro-BNP eventually came back at a kagillion, but his chest x-ray (obtained long after the nitro was given) looks benign. This complicates the dialogue with the admitting team.
“Hey, I don’t have to stay the night, do I?”

Thursday, July 9, 2015

The skillful use of the stethoscope is a key element of the
physical exam. Introduced in 1816, it afforded an unprecedented “view” inside
the body. Since then it has evolved to become synonymous with being a physician
(as well as nurse, paramedic, tech, etc.

But regardless of all these new
technologies, we all keep carting around our space-age versions of Laënnec’s
hollow wood stick, draped around our necks, ready to
bonk us in the eye if we make any sudden moves. Why?

We all occasionally joke that these diagnostic devices serve mostly
as “doctor jewelry,” and that we will always use a CXT, CT, MR, or whatever, to confirm our auscultations.
However, if the conversation turns serious, we will solemnly avow the sacrosanct role of the hollow stick.
“Nothing can replace a thorough Hx and P,” we intone, “nothing.”

We are, in that moment, the most harmful species of liar – the liar that believes the lie.

"Jerry, just remember. It's not a lie... if you believe it."

We need to stop, take
a deep breath, look ourselves in the eye, and admit that we have not been truthful
with thine own self. Dare to say the following; first
while alone in your locked bathroom, then in a safe 12-step environment, and
then eventually in public:

The stethoscope is a vestigial element of the physical exam, and ought to be
retired.

Second, the stethoscope sucks (or blows?)

While revolutionary in its day, the 'scope has seen its
diagnostic performance plummet as medicine progressed.Pneumonia
provides the best example of the limited contemporary accuracy of the stethoscope.

A systematic
review in the Emergency Medicine Journal concluded that "pneumonia
cannot reliably be confirmed or excluded by auscultation, or indeed physical
examination, alone.” The most recent study
in that review looked at patients coming into the ED with “chest symptoms,” and
looked at how the diagnostic impression changed from pre- to post-auscultation,
and then post-discharge. The vast majority of the time, about 95%, the clinical
impression did not change after using the sacred hollow stick.

Pneumonia, in
particular, was diagnosed correctly in 45%
of patients with history alone, and only improved to 49% after the exam.

An
earlier study looked only at CXR-verified pneumonia, and blinded the auscultators to the
clinical history. It wasn’t pretty – the sensitivity of the 3 examiners ranged
from 47% to 69%. Specificity wasn’t
much better.

This all comports with a JAMA
metaanalysis from 1997 that concluded that “no
individual clinical findings, or combinations of findings, that can rule in the
diagnosis of pneumonia.” Specifically, while one study was wildly bullish on
egophony, all the auscultation signs were of variable sensitivity, and
generally low yield.

Compare
this to using ultrasound:

While some authors have stated that “highly-skilled
sonographers“ are required to diagnose pneumonia with ultrasound, a recent study required
pediatric EM doctors to undergo only 1
hour of training. Despite this limited education, the sensitivity and
specificity of US for CXR-proven consolidation was 86% and 89%. However, another study, using CT
scan as the gold standard, found US to be far moresensitive than CXR. A raft of other studies have come out in the last few years (do they ultrasound anything but lungs in Italy?), backing up these results.

So, why are you carrying that MRSA
biofilm-vehicle around the same neck your kids touch?

If you really need some jewelry to identify you as a doc, you can get a
stethoscope earring. Cute as heck, and unlikely to get covered in MRSA, or give
you a black eye.

Thursday, June 18, 2015

This material is educational, and is not intended to serve
as hospital protocol.

Mostly, it's here to serve a quick reference for myself, and for impromptu discussions with PAs and residents.

SUMMARY

Suspected SBO

Oral contrast is contraindicated
in suspected SBO.

IV contrast is preferred, but not required.

Suspected
appendicitis

Oral contrast is not required, but may be beneficial in extremely thin individuals (e.g. BMI
< 18), or non-obese children.

Suspected
diverticulitis

Oral contrast is not required

Unclear etiology

PO contrast is suggested by some experts in undifferentiated
abd pain if the patient

1)Is very thin (e.g. < 120 pounds, BMI <
18);

2)Has had a Roux-en-Y gastric bypass; or

3)Has and inflammatory bowel disease that could
produce a fistula

Discussion and References

SBO

Per the American
College of Radiology guidelines, in a patient with suspected SBO, PO
contrast is contraindicated. They explain that: “Oral contrast will
not reach the site of obstruction, wastes time, adds expense, can induce
further patient discomfort, will not add to diagnostic accuracy, and can lead
to complications, particularly vomiting and aspiration.”

Multiple studies have shown that the use of PO contrast does
not increase the accuracy of the diagnosis of appendicitis (references below).
An editorial in a
recent radiology journalconcluded that “routine
administration of oral contrast medium may not be necessary in the setting of
suspected acute appendicitis.” American
College of Radiology guidelines state that PO contrast “may not be
needed,” leave the decision to use PO contrast to “institutional preference.”

Some have suggested that PO contrast
might be needed in extremely thin individuals (e.g. BMI < 18). See the discussion below in "Unclear etiology."

A 2009 randomized study in the American
Journal of Radiology found that “nontraumatic
abdominal pain imaged using 64-MDCT with isotropic reformations had similar
characteristics for the diagnosis of appendicitis when IV contrast material
alone was used and when oral and IV contrast media were used.”

A 2011 retrospective study in the Journal of Surgical Research
found that oral contrast did not reach the cecum in 1/3 of patients.
Furthermore, “there appears to be no diagnostic compromise in those without
contrast in the terminal ileum.

A 2014 prospective study in the Annals of Surgery
concluded that: “Enteral contrast should be eliminated in IV-enhanced CT scans
performed for suspected appendicitis.”

Diverticulitis

The American
College of Radiology guidelines state that PO contrast “may be helpful
for bowel luminal visualization.” Despite this, they conclude that “regardless
of the [the use or lack of IV or PO contrast], the accuracy is high for
depicting findings of acute diverticulitis.”

A 2006 prospective study in Emergency Radiologylooked
at patients with undifferentiated abdominal pain in the ED; 1/5 of them had LLQ
tenderness, and diverticulitis was the second-most common suspected diagnosis. All
patients had CT scans with and without PO contrast; no IV contrast was used. Although there were discordant
interpretations between the (+) PO and (-) PO CT scans, the authors found that
a “significant portion of the discordance was attributable to interobserver
variability.” Thus, it would appear that a CT scan without either PO or IV contrast
could be accurate in the diagnosis of diverticulitis.

Unclear
etiology

Oral contrast may not be needed for undifferentiated
abdominal pain, as per the discussion of the study in Emergency
Radiology noted above.

However, in a 2012 study in Emergency
Radiology that examined the use of PO contrast in undifferentiated
non-traumatic abd pain, the authors excluded 2 groups of patients. They excluded all “subjectively thin”
patients, but did not provide cut-offs. They noted the research that suggests
this exclusion is unnecessary, and may be dropped in the future. They also excluded patients at high risk for
having an intra-abdominal fistula. Primarily, they targeted patients who had had
a Roux-en-Y gastric bypass, or who had IBD, disposing them to fistula
formation.

Thursday, June 4, 2015

It was a classic “good news/bad news” sign out.

The attending who was signing out to me admitted that this wasn't the cleanest sign-out, but they had a plan.

The bad news: the patient likely had a shoulder dislocation, but the read on the X-ray was equivocal.

"Can I order a clinical correlation?"

Given this unclear picture, the plan was to try sedation, and pop it back in place.

The good news: the attending had already tasked a senior
resident and the orthopedics PA-C to perform the sedation and (attempted)
reduction, and they were champing at the bit to do the procedure.

My evaluation

I looked at the X-ray, and re-examined the patient. As he was young chubby guy, it
was difficult to be sure of the exam. Since both my exam and the X-ray were so
unhelpful, I stalled the resident and PA-C while I grabbed the ultrasound.

Now, ultrasound is not usually thought of as a great test
for shoulder dislocation. The usual approach to definitively excluding a
glenphumeral dislocation (especially posterior dislocation!) is to obtain an
axillary view, shooting up through the armpit. And of course we can always get a CT of the joint.

But you can get much the same image with the ultrasound. So,
placing the probe on the posterior shoulder, I aimed anteriorly, with the left
side of the screen oriented to the lateral aspect, like this:

This produced a clear image of the glenohumeral joint:

As usual, US is best appreciated dynamically, with this clip showing the patient rotating his arm:

I hope you can see how the head of the humerus is well-seated in the glenoid. But despite
this dazzling proof, x-rays and a CT
were needed to convince ortho that the shoulder was not dislocated,
and that no sedation and tugging were needed.

The (ionizing radiation) proof

The axillary view of the shoulder X-ray (needs to be specifically ordered), oriented similarly to the US:

The CT of the shoulder, with the slices and orientation similar to the US:

If you want to check out some other US examples of dislocated shoulders, you can also check out this great video from ALiEM:

Ultrasound for the ... Wait, what?!

I would have liked to say this was an ultrasound win, but I'm not so sure. The downsides of this approach, in retrospect, were:

The patient didn't get to enjoy some of our high-grade ketamine;

We didn't get to high-five each other after our "subtle reduction;" and

Sunday, March 8, 2015

What is high-flow nasal cannula (HFNC) therapy, and, more importantly, does it work? A recent segment on EM:RAP went into a fair amount of detail about the putative mechanism, so I’ll leave that alone.

What that segment left out, though, was any discussion of the published evidence pointing to the benefit of HFNC. And indeed, while there are a lot of anecdotal reports and personal testimonials, the actual data hasn’t been clearly discussed. Here’s a quick review of what we currently know.

2. Infants

It may help prevent intubation of little kids with bronchiolitis, although the data is weak. The two most relevant studies were retrospective chart reviews, using a before-and-after design, looking at overall rates for intubation in the time period after HFNC was introduced to the pediatric service. Nonetheless, McKiernan found that intubation rates for bronchiolitis dropped from 23 % to 9%, and Schibler found the rate plummeted for 37% to 7%!

McKiernan 2010

This may end up being one of the best-supported roles for HFNC, and high-quality studies are in progress that could help clarify the issue.

3. Adults

The initial trials in adults have demonstrated modest improvements in oxygenation, but haven't studied patient oriented-outcomes. For example, one study found that oxygenation mildly increased after HFNC initiation, but no control group was used.

A single-author review, otherwise very bullish on HFNC therapy, conceded: “although some clinicians may have the impression that in some instances, use of HFNC has avoided intubation, this has not been shown in a controlled trial.”

“While theoretical advantages exist over standard nasal cannula and face mask oxygen, current evidence does not definitively demonstrate superiority to other methods of respiratory support. Few studies have focused on clinical outcomes beyond common respiratory parameters. Given the potential lack of consistency of positive pressure generated with current HFNC systems, NIV such as CPAP and bilevel positive airway pressure should still be considered first line therapy in moderately distressed patients in whom supplementation oxygen is insufficient and when a consistent positive pressure is indicated.”

Bringing it home!

Being an “early-adopter” is cool – if you’re lining up to get the new iPhone or Zune! In medicine, however, it doesn’t often pay to jump on a bandwagon before the data is in. (Want to buy some Xigris cheap?) We are being encouraged to try a new therapy that uses proprietary (proprietary = $) devices, with soft indications, scant evidence, but with touted outcomes such as “improved comfort,” instead of mortality or rates of intubation. We should be cautious.

Particularly concerning is the uncritical enthusiasm for the use of this device in situations that either clearly call for other therapies, or for no therapy. For example, some describe the utility of HFNC in patients who are “extremely hypoxic,” but there is little evidence that HFNC improves outcomes in this population.

HFNC is probably more useful for precisely titrating FIO2 in the (mythical?) CO2 retainer. But if there is a concern about the PaCO2, why not use a proven therapy like NPPV that we know saves lives?

Lastly, some clinicians promote the use of HFNC for CHF, since there is (wink, wink) a “PEEP component,” but that’s a patient who needs CPAP or BiPAP as well, since we already have proven a mortality benefit in that population as well.

Sure, you can relax, talk with family, and eat while wearing HFNC, but if you are so dead set on wolfing down a sandwich, you probably don’t need an expensive, unproven therapy. You need 2 liters per minute, and a floor bed!